Specialty Optical Fibers Handbook

use of POF for LAN applications increased and there was an interest to further

increase their transmission capacity, the focus centered on developing fabrica-

tion techniques for GI POFs. Among the techniques available for GI POF

manufacturing are gel polymerization, extrusion, centrifuging, photochemical,

and others.

20.7.1 SI POF: Preform and Extrusion Method

In the preform method, a cylinder is produced that already has the index

profile of core and cladding while having a much larger diameter. During the

drawing process, the diameter is reduced until the desired size has been reached

(Fig. 20.33).

Ideally, the index profile should be maintained